Guys, I came across an Android App called Dailyroads Voyager, which transforms your Android mobile into a dash cam. It overlays it with GPS information like speed, elevation and Lat/Long. It is pretty customisable in terms of recording quality (hence size), frame rates etc. All you have to do is mount your camera in landscape mode (doesn't work in portrait) on your windscreen and turn it on. I have customised mine to record video in chunks of 300seconds.
So, how it works is that once a video of 300 sec is recorded, it transfers that file into a tempvideos folder. I have set the limit of the temp folder to three files. So, as the fourth file is ready for transfer to the folder, the first file is deleted. This ensures that your memory card is never filled up and you have the last 15 minutes (Customisable. I have set 3 videos of 300s each) of video recorded and available.
In addition to this, it has a one-touch retaining of videos. In case something interesting happens and you want to retain that video, you can configure it to retain the video on a touch. The best part is you can also set it to retain a video in case of an impact. You can set the impact acceleration. I have set mine to 3g. So, anytime I have an impact which exceeds 3g as sensed by the phone accelerometer, it will automatically retain that video. Too good to be true for a free app? So, whats the catch?

Well, the videos can be played back along with the overlay of speed, elevation and coordinates only within the software on the phone. When the same video is played as a standalone file in a third party video player, the overlay does not appear. For that, there is a need to upload the files to the server and buying credits for processing the file. They will write the overlay and then the file can be downloaded.

Frankly, I like this software not because I can't afford to buy another gadget to function as a dash cam but I would like to multitask my already mounted mobile phone. Saves space, lesser wires and it can run in the background while you have other software such as Google maps running in the foreground. I found it really good. Do Google it up and try it out if you have an android phone.

Unfortunately, all photographs and videos that I had recorded have all got washed away due to my phone getting bricked due to my careless monkeying around with Custom ROMs!! Just revived the phone (sans data, alas!). So, will record new ones and update this thread.

Wow. This could be quite useful, but too bad I wear glasses and getting sun glasses like that isn't possible.
Also, my dad had a similar pen-camera the quality was very crappy, I believe it would be same for this..
And 3k seems pretty steep, especially when coming from SnapDeal(too many unsatisfied customers). I believe it would cost less than 1k in local markets, finding them would be difficult though. :P

We know the benefits - captures the events which can be used as witness in the event of an accident. of course, capture a flying cow or a meteor

The camera is quite commonly used by law enforcement agencies in many countries. I noticed extensive use of the in-dash camera in fast-east countries. I believe the insurance firms value the video as witness, if you are claiming for damage.

The online deals shows camera ranging from $50 to $250 or above; $100 will give you decent product. Supposed to be easy to install.

Friend of mine got one in Punto. It was an el cheapo Chinese one. Works fine. The cigaretter lamp charger triggers the cam. Recording file size can be set, so that it will save file once the limit is reached. Older files will be rewritten once memory is full.

I have used my Lumia 520 as dash cam, but no external triggers.

Now 1080p resolution wide-angle cams are available at decent price, also dual cams for front and rear.

I've been too looking to install one in my car ever since I purchased my first four wheeler, but since had little knowledge, I had been using my mobile as one but it eats up the battery and too much vibration due to the holder being weak, and I would rather want a very much dedicated Dash Cam whose sole purpose is to record on road movements and which can come in handy in case of any accident happens.

While I have found many on ebay.in and .com, I still am in search for one that has auto recording feature, i.e records even when the car's still/in parking mode cause there have instances when people hit your car and run away, actually it happened with me inside my society, someone had hit it and created a dent on the right fender and kids are pretty notorious, so I want one for that purpose too, would be glad if someone could help me find one according to my requirements.